Refrigerated display unit



June 1965 G. K. BENTLY ETAL 3,185,135

REFRIGERATED DISPLAY UNIT Filed Jan. 5, 1963 3 Sheets-Sheet 1 p fi 24 j J G'EORG-E g w .2; H5. 5: G-Leun W. MA'n-us ATTOR N EYS United States Patent 3,186,185 REFRIGERATED DESPLAY UNIT George K. Bently and Glenn W. Mathis, Kendallville, Ind., assignors to McCray Refrigerator Company, Inc, Kendallville, Ind., a corporation of Indiana Filed Jan. 3, 1963, Ser. No. 249,167 Claims. (Cl. 62-255) This invention relates to a refrigerated display unit of the upright type having means to maintain low shelf temperatures for the preservation of frozen foods and comprising individual cold air supplies for each shelf and a curtian of cold air flowing downwardly in front of all of the shelves.

Refrigerated upright display units have recently attained considerable popularity because they can dis-play frozen goods to the consumer much more effectively than can the usual refrigerated open-top bin. The typical upright display unit has a plurality of shelves located one above another which display the frozen goods carried thereon closer to the eye level of the consumer and render it easy to enable one to reach into the unit and pick up a frozen food package. Such units play an important part in increasing consumer buying for the reason, among others, that the display of the goods can be kept neat and is not disturbed and jumbled up by the customers as is frequently the case with bin type units. These upright units, however, tend to lose a large quantity of cold air which spills out the front of the unit and, consequently, they require much larger refrigerating machines and have considerably higher operating costs than the open-top bins which have heretofore been prevalent in the frozen food field.

It has been discovered that the loss of cold air can be decreased substantially by providing a curtain of cold air flowing downwardly in front of all of the shelves of the unit and drawing this air into the unit near the bottom, subsequently recooling and recirculating it. This cold air curtain, however, still allows some cold air to escape from the lower portions of the unit, which not only lowers the efficiency of the refrigeration system but also produces a discomforting chill :to the feet of customers standing in front of the display unit. This, of course, tends to keep the customer away from the unit or at least causes him to stand in front of it for a shorter time and, consequently, to purchase fewer items than otherwise.

The refrigerated upright display unit of the present invention overcomes the above disadvantages by providing a confining curtain of warm air flowing upwardly outside the curtain of downwardly-flowing cold air. The rising hot air tends to direct the cold air inwardly into the unit and also tends to raise the temperature of any cold air which spills out of the unit. Thus, any air reaching the feet of the consumer is substantially warmer than otherwise and any discomfort to him is either eliminated entirely or greatly minimized. The hot air flow not only reduces cold air losses so as to increase the efficiency of the refrigerating system, but also produces little or no discomfort to the consumer so that he will remain in front of the refrigerated display unit longer than otherwise and will tend to purchase larger quantities of the frozen food displayed therein.

Upright refrigerated display units heretofore known also have supplied the cold air to the spaces between the shelves from points such that the frozen foods carried on the shelves have tended to interrupt and hamper the flow of the cold air. These units also have lacked proper flow control so that certain of the shelves received a greater volume of cold air than others.

The display unit of the present invention overcomes these defects by providing air supply outlets for the spaces between the shelves at the upper rear portions thereof so that most of the cold air is directed above frozen food packages carried on the shelves and the outlets are at least partially hidden from view by the next shelf thereabove.

Each of the outlets for each of the shelf spaces also has its own supply duct which provides a separate supply of air therethrough with the ducts containing flow-control restrictions to assure va proper flow of air for each of the shelf spaces as wellas for the curtain of downwardly flowing cold air.

The refrigerated display unit of the invention also has heating wires on the lower surfaces of each of the shelves which can be operated during a defrost cycle of the unit to remove any frost that might have accumulated on the shelves from the cold air supplied to the shelf spaces. The heating wires are supplied with current through flexible leads which enable the shelves to be adjusted vertically. The flexible leads, in turn, are provided with removable electrical connections which can be separated to enable the shelves to be taken out completely for cleaning, repair, 'or replacement. Under some circumstances, the heating wires will be left on continuously, and under other circumstances current will be supplied only during a portion of the operating cycle. Heater wires directly in back of each price tag molding may also be used.

For maximum efficiency, the refrigerated display unit according to the invention has a curtain of air-pervious material which can be operated to close off the front of the unit over night, for week-ends, and the like. It has been found that an air impervious curtain becomes coated with frost over a period of time as it is cooled by the refrigerated unit below the dewpoint of the ambient air outside the unit. Hence, the curtain could not be rolled up until the frost is removed and the material dried. It has been discovered, however, that if the night curtain is made slightly pervions to air, this problem is eliminated and no frost at all will form on the curtain. This apparently is due to the fact that the curtain passes a slight amount of air therethrough which apparently keeps the curtain itself above the dewpoint of the ambient air.

It is, therefore, a principal object of the invention to provide an improved upright refrigerated display unit having the features discussed above.

Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is an overall view in perspective of a refrigerated display unit embodying the principles of the invention;

FIG. 2 is an enlarged, schematic view in vertical cross section taken along the line 2-2 of FIG. 1;

FIGS. 3, 4, and 5 are enlarged views of portions of the unit shown in FIGS. 1 and 2;

FIG. 6 is a bottom view of a shelf incorporated in the display unit of H68. 1 and 2; and

FIG. 7 is an enlarged view in vertical cross section of an edge portion of a shelf of the display unit.

Referring to the drawings, and more particularly to FIG. 1, a refrigerated display unit embodying the inven tion is indicated generally at 10 and includes a plurality of refrigerated display sections 12 with a continuous, longitudinally-extending top assembly 14 and a continuous, longitudinally-extending base assembly 16 and end walls 18 and 20. The top, base, and end Walls 14-20 give the unit 10 an appearance of being a single integrated piece in spite of the fact it is actually made up of a number of the modules or sections 12. In practice the sections 12 are, for example, made in 8 foot and 12 foot lengths and are assembled into 8, 12, 16, or 20 foot cases with the shelves being 4 feet long so that two or three shelves are used in each row in each section. One 8 foot section and one 12 foot section are shown in FIG. 1.

Each of the sections 12 is substantially complete within itself, having its own shelves, duct- 101k, and cooling coils, although several or all of the sections have a common, remotely-located compressor and condenser coil and all of them have the common top and base assemblies 14 and 16. When a number of the sections are to be used in the single integrated display unit they can be suitably attached to one another in any of a number of Ways known in the art.

As shown in FIG. 2, each of the sections 12 includes a bottom shelf 22 and a plurality of upper shelves 24, 26, 28 and 30. The bottom shelf 22 is intended to remain in a fixed position and slants outwardly for easier access to frozen food packages located in a basket 32 supported on the shelf 22. The upper shelves 24-30 may slant inwardly slightly for better accessibility and each is shorter than the one above it although the front edges of all shelves are in the same vertical plane except for the top shelf 30. This arrangement makes room for ductwork behind the shelves and also better accommodates a curtain of cold air flowing downwardly in front of the shelves, but is not essential. The low shelf 24 is suported in any suitable manner as by upper side brackets 34 while the shelves 26-30 are supported as by lower side brackets 36, 38, and 40. The brackets 34-40 have suitable ears which are engaged in slots in upright supporting members 42 located in each of the sections 12. The brackets thereby can be moved upwardly and downwardly with respect to the supports 42 to adjust the vertical disposition of the shelves 24-30 and to enable them to hold frozen food packages of unusual sizes or shapes more efliciently. Each of the shelves 24-30 has a channel or price tag molding 42 along the front edge thereof to receive price markers or the like.

A main air dehydrating and cooling coil assembly 44 is located in a space 46 below the bottom shelf 22 and receives refrigerant from a remote compressor unit which supplies several of the coil assemblies 44. The coil assembly 44 is designed not only to cool air passing therethrough to a temperature below that of a second, upright coil assembly 48 but also to bring the air below the dewpoint to extract as much as possible of the moisture which is picked up during circulation. In this manner, frost-free operation is virtually assured for the coil assembly 48, through which the air subsequently passes, and this coil is used to reduce the air temperature to, for example, F. Heating coils or electrical heating element 50 and 52 are located upstream of the coil assembly 44 and a heating coil or electric heating device 54 is located upstream of the coil assembly 48, these heating coils being operated when the coil assemblies 44 and 48 are to be defrosted. Water formed by melting frost from the coil assemblies 44 and 48, is then drained through a passage 56. This passage 56 can carry the water to a drain line (not shown) located in a base chamber 58, which can extend to any remote disposal point. The heating device 54 also prevents the build-up of ice around the drain 56.

A fan 60 is mounted above the main coil assembly 44 and draws air from an inlet 62 through a passage 63 located immediately below the shelf 22. The air is then forced through the coil assemblies 44 and 48 and is directed through five vertical ducts or passages 64-74. The ducts 64-74 are formed, in the present instance, by sheet metal partitions 76-84, each of which also forms a rear wall for the area between adjacent ones of the shelves 24-30. The partitions 76-84 extend substantially the Width of the section 12 and have suitable end walls (not specifically shown) which separate the ducts 64-74 from the corresponding ducts of an adjacent one of the sections 12. The partitions 76-84 also have suitable vertically disposed perforate stiffeners (not shown) which merely add rigidity to the partitions.

A horizontal partition at the inlets for the ducts 64-74 has orifices 86-94 formed therein to provide close control of air flow through the several ducts 66-74. The orifices 86-94 are larger at the back, in this instance, with the largest one being orifice 94 which controls flow of cold air through the duct 74 to an upper cold air chamber 96. A separate orifice 95 controls the air flow into the lower compartment below shelf 24 which is generally reserved for small cans of frozen juice and the like.

From the upper cold air chamber 96 the air is directed through an outlet 98 formed between an outer edge of a ceiling board 100 and a lip 102 which directs air downwardly in front of the outer edges of the shelves 22-30. This air moves uniformly downwardly past the shelves to the lower inlet 62 from which it is recirculated through the fan 60 and the coil assemblies 44 and 48. The cold air curtain thus formed is an important factor in keeping the cold air within the section 12 and the unit 10 and substantially increases the efliciency of the unit in this manner, causing a significant decrease in operating costs. The integrity of the cold air curtain appears to be maintained by an air flow in the forward direction from each of the shelf supply ducts 64-72, since this forward air flow tends to eliminate eddy currents in the air curtain which would otherwise be caused by the air passing across the front edge of the shelves or impinging on merchandise on the shelves. The control is such that a temperature suitable for frozen foods such as from 0 F. to -2" F., can readily be maintained at a point adjacent the front of the shelves 22, 24, 26, 28 and 30. As discussed previously, the cold air curtain tends to spill out of the unit 10 and over the base assembly 16 so that a large amount of cold air is still wasted increasing the cost of operation. This cold air flowing onto the floor of the store also is uncomfortable to customers standing in front of the unit 10 because it has a tendency to chill their feet.

In accordance with the invention, it has been discovered that a curtain of heated air can be provided immediately outside the cold air curtain to overcome the above disadvantage. The hot air curtain, flowing upwardly in front of the cold air curtain, appears to direct the downwardly flowing cold air inwardly and into the inlet 62 more effectively than if no hot air curtain were used. Consequently, with less cold air lost, the efficiency of the unit is improved. In addition, any cold air tending to spill out of the base assembly 16 and onto the floor mixes with air from the hot air curtain with the resulting mixture then either rising or flowing onto the floor at a much lower rate, depending on the ultimate temperature of the mixture. In either event, the consumer standing in front of the unit does not feel any air at all, if the mixture rises, or only feels a small amount of the warmer air which would be at or near ambient temperature. In the present instance, the heated air curtain is established by means of a suitable electric heating coil 104 (see FIG. 3) located in a narrow vertical duct or passage 106, the bottom of which communicates with a diagonal wall 108 having perforate inlets 110, wmle the upper end has outlet vanes 112 which direct the warm air slightly toward the cold air curtain. The passage 106 thus acts to set up convective heat flow as the coil 104 heats the air therein, thus causing it to rise and flow past the outlet vanes 112, and draw in air through the inlet perforations 110. Each of the ducts 64-74 terminates at its upper end in a vane assembly or outlet 114 (FIG. 4) which include a plurality of generally L-shaped vanes 116, 118 and 120, which can also be more gently curved, with a single vane also being suitable in some instances. Each of the vanes 116-120 intercepts part of the air flowing upwardly through the associated duct, such as the duct 68 as shown In FIG. 4, with the remaining air flowing upwardly between the vane 120 and the partition 80. The vanes 116-120 thus direct the cold air over the frozen food on the associated lower shelf, in this instance the shelf 26, so that it is almost impossible for food on the shelf to seriously inhibit the fiow of cold air. The vane assembly 114 also is substantially hidden from view, being directly under the shelf thereabove and at the upper rear portion of the space between adjacent shelves While the shelves 24-30 may be raised somewhat, the relative position of the outlets 114 is not changed significantly. As previously stated the air flowing from the outlets 114 over the merchandise not only maintains a very low temperature for the goods but also assists in controlling the flow of the front air curtain by eliminating eddy currents therein.

As shown in FIG. 6, each of the shelves 24430 and the ceiling panel 100 has heater wires 122 attached to the lower surface thereof and distributed in a manner to effect uniform heating of this surface. As shown in FIG. 4, the wires are connected to leads 124 which are connected to a source of current through a plug 126 ccoperating with an outlet 128 mounted in the associated rear wall of the section 12. The outlet 128 is connected to a suitable source of current through lines 130. The heater Wires 122 supply a small amount of heat to the lower surface of the shelves 2430 each time the unit is defrosted, if desired, with the small amount of frost accumulated thereon from the adjacent outlet 114 turning to water and being evaporated by air blown through the coil assemblies 44 and 48. However, the wires 122 can supply heat to the shelves 24-30 continuously to prevent formation of frost. The flexible leads 124 for the heater wires 122 enable the associated shelf to be adjusted vertically without disconnecting these wires. Further, the plug 126 enables the entire shelf to be removed for cleaning, repair, or replacement with minimum trouble. The shelves themselves are of simple, solid construction and are capable of withstanding considerable abuse. At the same time, they are inexpensive and very easy to clean, having unbroken, plane major surfaces.

The price tag molding 42 at the front edge of the shelves may also have heater wires 132 to prevent frost accumulation at this point where the case is used in humid climates. The wires 132 preferably heat the molding 42 continuously.

The upper lip 102 has heater wires 133 near the lower edge thereof to dissipate frost accumulating from the air supplied for the air curtain.

Although the upright unit is relatively efficient, it will be appreciated that losses decrease considerably if the front thereof is closed off during periods of inactivity, such as overnight or over weekends. For this purpose, each of the sections 12 has pull-down curtains 134 and 136 (FIGS. 1 and 5) which are stored out of the way on spring-loaded rollers 138 and 141 These are rotatably mounted within an upper chamber 142 extending longitudinally of the unit 10 and formed by the top assembly 14. Whether there is one or more of the curtains 134 and 136 for each of the sections 12, the curtains are in staggered relationship so that they overlap one another when pulled down. This relationship is shown in FIG. 1 wherein the curtain 136 is pulled completely down and the curtain 134 is shown in the process of being pifil'ed down, being about halfway between its retracted and extending positions. When in the lower position, the curtains can be held in place by hooks 144 which cooperate with projections 146 (FIG. 3) near the base of the unit and when in its lowered position the curtain is disposed between the cold air curtain flowing towards the inlet duct 62 and the warm air curtain emerging from the duct 106.

The curtains used for this purpose have had a tendency to reach a temperature below the dewpoint of the ambient air with frost then being formed. The frost build-up must be removed to retract the curtain, often a messy and timeconsuming operation. It has been found, however, that if the curtain is made of a pervious material which enables a slight amount of air to pass thereth-rough when the curtain is pulled down, frost is prevented. With such a curtain, apparently some warm air passes through it to the cold side to prevent the curtain from reaching a temperature below the dewpoint of the ambient air, with the result that the curtain remains free of frost.

The curtain preferably is made of a flexible insulating material such as organic or inorganic fabric. One fabric suitable for this purpose is Dacron sail-cloth, weighing 5-8 ounces per square yard and having a 60 x 40 count. Another fabric which has been used is glass fiber cloth such as is obtainable from Hess-Goldsmith Corporation under the designation HG-116. A wire screen cloth can also be employed. Ideally, the mesh should be a small as possible, slightly larger than that at which frost will form. In any even, the fabric has a porosity smaller than that of a mesh screen which is too large to be efiicient. By definition a 100 mesh screen has openings 0.0059 inch square. Usually with night curtains, frost tends to form at the lower portions thereof even if it does not elsewhere. Any such tendency in the present instance is overcome by the hot air curtain embodied in the unit 10. Rather than a porous curtain, one employing heating elements can be used, with the elements turned on when the curtain is extended.

In a specific operating example for the above unit, the air drawn through the inlet 62 by the fan 60 is cooled in two steps to a temperature as low as 35 F. at which temperature it is expelled through the outlets 114. The air then flows over and downwardly through the frozen food on the shelves 22-30 and reaches a temperature of about l0 F. at the front thereof. The air then merges with the air curtain and moves downwardly, being directed and contained in part by the cold air curtain with the cold air curtain in turn being directed, at its lower end, inwardly and through the opening 62 by the warm air flowing from the heater 104 past the outlet vanes 112.

Various modification of the above described embodiments of the invention will be apparent to those skilled in the art and it is to be understood that such modifications can be made without departing from the scope of the inventiom'if they are within the spirit and tenor of the accompanying claims.

We claim:

1. An upright refrigerated display unit comprising a plurality of sections, each of said sections comprising a plurality of vertically spaced shelves, each having uninterrupted upper and lower surfaces, means for removably supporting said shelves above one another and enabling each shelf to be vertically adjusted, means forming a plurality of vertically disposed ducts behind said shelves and forming rear Walls for the spaces between said shelves, means forming an orifice for each of said ducts to control flow therethrough, means forming an outlet in the rear wall between each adjacent pair of shelves, each outlet being closer to the upper one of the pair of shelves, all but one of said vertical ducts terminating at separate outlets, each of said outlets including a plurality of vanes directed slightly downwardly and positioned to intercept approximately equal amounts of air flowing through the associated duet, means forming an additional outlet above the front edges of said shelves and connected to the remaining duct to direct a curtain of cold air downwardly in front of said shelves, means form-ing an inlet at the front edge of the lower shelf, a passage connecting said inlet with said vertical ducts, fan means and cooling means in said passage to move the air from said inlet toward said vertical ducts and to cool the air, drain means communicating with said passage to drain water resulting from melted frost accumulated on said cooling means, a heating device near said drain means to prevent the water from freezing, means forming an upright passage outside said inlet, heating means in said upright passage to establish an upwardly moving curtain of warm air outside the curtain of cold air, a heating element at the lower surface of each of said shelves below which there is a cold air outlet, a price tag molding at the front edges of at least some of said shelves, an additional heating element behind each of said price tag moldings, flexible means to connect said heating elements to an electrical supply outlet in each of enemas said sections for each of said shelves having a heating wire to supply current through the heating elements, whereby each of said shelves can be adjusted vertically without interrupting the electrical connections and can be removed from the section, a roller rotatably supported in front of and above said shelves, and a curtain finer than 100 mesh mounted on said roller for retraction thereon and for movement downwardly in front of said shelves and between the cold and warm air curtains.

2. An upright refrigerated display unit comprising a plurality of vertically-spaced shelves, means for removably supporting said shelves above one another and enabling each shelf to be vertically adjusted, means forming a plurality of vertically-disposed ducts bClJll'ld said shelves, means forming an orifice for each of said ducts to control flow therethrough, means forming an outlet between and at the rear of each adjacent pair of shelves, each outlet being closer to the upper one of the shelves, all but one of said vertical ducts terminating at separate outlets, means forming an additional outlet above the front edges of said shelves and connected to the remaining duct to direct a curtain of cold air downwardly in front of said shelves, means forming an inlet at the front edge of the lower shelf, a passage connecting said inlet with said vertical ducts, fan means and cooling means in said passage to direct air from said inlet to said vertical ducts and to cool the air, drain means communicating with said passage to drain water resulting from melted frost accumulated on said cooling means, a heating device near said drain means to prevent the water from freezing, means forming an upright passage outside said inlet, heating means in said upright passage to establish an upwardly moving curtain of warm air outside the curtain of cold air, a heating wire at the lower surface of each of said shelves, a price tag molding at the front edges of at least some of said shelves, an additional heating element behind each of said price tag moldings, a roller rotatably supported in front of and above said shelves, and an air pervious night curtain mounted on said roller for retraction thereon and for movement downwardly in front of said shelves and between the cold and warm air curtains.

3. An upright refrigerated display unit comprising a plurality of vertically-spaced shelves, means for removably supporting said shelves above one another and enabling each shelf to be vertically adjusted, means forming a plurality of vertically-disposed ducts behind said shelves, means forming an orifice for each of said ducts to control flow therethrough, means forming an outlet between and at the rear of each adjacent pair of shelves, each outlet being closer to the upper one of the shelves, all but one of said vertical ducts terminating at separate outlets, means forming an additional outlet above the front edges of said shelves and connected to the remaining duct to direct a curtain of cold air downwardly in front of said shelves, means forming an inlet at the front edge of the lower shelf, a passage connecting said inlet with said vertical ducts, fan means and cooling means in said passage to direct air from said inlet to said vertical duct and to cool the air, means forming an upright passage outside said inlet, heating means in said upright passage to establish an upwardly moving curtain of warm air outside the curtain of cold air, a heating wire at the lower surface of each of said shelves, a roller rotatably supported in front of and above said shelves, and an air pervious night curtain mounted on said roller for retraction thereon and for movement downwardly in front of said shelves and between the cold and warm air curtains.

4. An upright refrigerated display unit comprising a plurality of vertically spaced shelves, means forming a plurality of vertically disposed ducts behind said shelves, means forming an outlet between each adjacent pair of shelves, all but one of said vertical ducts terminating at separate outlets, means forming an additional outlet above the front edges of said shelves and connected to the remaining duct to direct a curtain of cold air downwardly in front of said shelves, means forming an inlet at the front edge of the lower shelf, a passage connecting said inlet with said vertical ducts, fan means and cooling means in said passage to direct air from said inlet toward said vertical ducts and to cool the air, means establishing an upwardly moving curtain of warm air outside the curtain of cold air, a heating wire at the lower surface of each of said shelves, a roller rotatably supported in front of and above said shelves, and a night curtain pervious to air mounted on said roller for retraction on said roller and for movement downwardly in front of said shelves and to a position between the cold and warm air curtains.

5. An upright refrigerated display unit comprising a plurality of vertically spaced shelves, means forming a plurality of vertically-disposed ducts behind said shelves means forming an outlet between each adjacent pair of shelves, all but one of said vertical ducts terminating at separate outlets, means forming an additional outlet above the front edges of said shelves and connected to the remaining duct to direct the curtain of cold air downwardly in front of said shelves, means forming an inlet at the front edge of the lower shelf, a passage connecting said inlet with said vertical ducts, fan means and cooling means in said passage to direct air from said inlet toward said vertical ducts and to cool the air, and means adjacent said inlet to establish an upwardly moving curtain of warm air outside the curtain of cold air at the lower end of said cold air curtain to prevent spillage of said cold air.

6. An upright refrigerated display unit comprising a plurality of vertically spaced shelves having smooth upper and lower surfaces, means removably supporting said shelves above one another and enabling each shelf to be vertically adjusted, air refrigerating means within said display unit, means for draining water resulting from melted frost from said refrigerating means, a heating device near said drain means to prevent ice build-up near said drain means, outlet means just below at least some of said shelves for supplying cold air from said refrigerating means to the space between said shelves, means to heat the front edges and the lower surfaces of those shelves having cold air outlets therebelow, and means for supplying electricity to said heating means during a defrosting cycle of said refrigerating means.

7. An upright refrigerating display unit comprising a plurality of vertically spaced shelves having smooth upper and lower surfaces, means removably supporting said shelves above one another and enabling each shelf to be vertically adjusted, air refrigerating means within said display unit, outlet means just below at least some of said shelves for supplying cold air from said refrigerating means to the space between said shelves, means to heat the lower surfaces of those shelves having cold air outlets therebelow, and means for supplying electricity to said heating means during a defrosting cycle of said refrigerating means.

8. A refrigerated display unit comprising a plurality of vertically spaced shelves, means for supplying cold air to the area adjacent said shelves, a night curtain, means located in front of and below said shelves for establishing an upwardly moving curtain of warm air in front of said shelves, and means for supporting said night curtain in front of said shelves and inwardly of the warm air curtain.

9. A refrigerated display unit comprising a partially enclosed display shelf, means for supplying cold air to the area adjacent said shelf, a curtain, an electrical heating element carried by said curtain for heating same, and means for supporting said curtain in front of said shelf to separate the shelf space from the ambient air.

10. A refrigerated display unit comprising a partially enclosed display shelf, means for supplying cold air to 9 the space adjacent said shelf, a curtain which is pervious to air, said curtain being a fabric with a lesser porosity than a 100 mesh screen, and means for supporting said curtain in front of said shelf to separate the shelf space from the ambient air.

References Cited by the Examiner UNITED STATES PATENTS 917,705 4/09 Benjamin 312-297 Weber 62256 Swanson 62255 Dickson 62256 Simons 62256 Detwiler 62275 Lamb 62256 Dickson 62419 Dickson 62256 Ural 62256 WILLIAM J. WYE, Primary Examiner.

ROBERT A. OLEARY, Examiner. 

1. AN UPRIGHT REFRIGERATED DISPLAY UNIT COMPRISING A PLURALITY OF SECTIONS, EACH OF SAID SECTIONS COMPRISING A PLURALITY OF VERTICALLY SPACED SHELVES, EACH HAVING UNINTERRUPTED UPPER AND LOWER SURFACES, MEANS FOR REMOVABLY SUPPORTING SAID SHELVES ABOVE ONE ANOTHER AND ENABLING EACH SHELF TO BE VERTICALLY ADJUSTED, MEANS FORMING A PLURALITY OF VERTICALLY DISPOSED DUCTS BEHIND SAID SHELVES AND FORMING REAR WALLS FOR THE SPACES BETWEEN SAID SHELVES, MEANS FORMING AN ORIFICE FOR EACH OF SAID DUCTS TO CONTROL FLOW THERETHROUGH, MEANS FORMING AN OUTLET IN THE REAR WALL BETWEEN EACH ADJACENT PAIR OF SHELVES, EACH OUTLET BEING CLOSER TO THE UPPER ONE OF THE PAIR OF SHELVES, ALL BUT ONE OF SAID VERTICAL DUCTS TERMINATING AT SEPARATE OUTLETS, EACH OF SAID OUTLETS INCLUDING. A PLURALITY OF VANES DIRECTED SLIGHTLY DOWNWARDLY AND POSITIONED TO INTERCEPT APPROXIMATELY EQUAL AMOUNTS OF AIR FLOWING THROUGH THE ASSOCIATED DUCT, MEANS FORMING AN ADDITIONAL OUTLET ABOVE THE FRONT EDGES OF SAID SHELVES AND CONNECTED TO THE REMAINING DUCT TO DIRECT A CURTAIN OF COLD AIR DOWNWARDLY IN FRONT OF SAID SHELVES, MEANS FORMING AN INLET AT THE FRONT EDGE OF THE LOWER SHELF, A PASSAGE CONNECTING SAID INLET WITH SAID VERTICAL DUCTS, FAN MEANS AND COOLING MEANS IN SAID PASAGE TO MOVE THE AIR FROM SAID INLET TOWARD SAID VERTICAL DUCTS AND TO COOL THE AIR, DRAIN MEANS COMMUNICATING WITH SAID PASSAGE TO DRAIN WATER RESULTING FROM MELTED FROST ACCUMULATED ON SAID COOLING MEANS, A HEATING DEVICE NEAR SAID DRAIN MEANS TO PREVENT THE WATER FROM FREEZING, MEANS FORMING AN UPRIGHT PASSAGE OUTSIDE SAID INLET, HEATING MEANS IN SAID UPRIGHT PASSAGE TO ESTABLISH AN UPWARDLY MOVING CURTAIN OF WARM AIR OUTSIDE THE CURTAIN OF COLD AIR, A HEATING ELEMENT AT THE LOWER SURFACE OF EACH OF SAID SHELVES BELOW WHICH THERE IS A COLD AIR OUTLET, A PRICE TAG MOLDING AT THE FRONT EDGES OF AT LEAST SOME OF SAID SHELVES AN ADDITIONAL HEATING ELEMENT BEHIND EACH OF SAID PRICE TAG MOLDINGS, FLEXIBLE MEANS TO CONNECT SAID HEATING ELEMENTS TO AN ELECTRICAL SUPPLY OUTLET IN EACH OF SAID SECTIONS FOR EACH OF SAID SHELVES HAVING A HEATING WIRE TO SUPPLY CURRENT THROUGH THE HEATING ELEMENTS, WHEREBY EACH OF SAID SHELVES CAN BE ADJUSTED VERTICALLY WITHOUT INTERRUPTING THE ELECTRICAL CONNECTIONS AND CAN BE REMOVED FROM THE SECTION, A ROLLER ROTATABLY SUPPORTED IN FRONT OF AND ABOVE SAID SHELVES, AND A CURTAIN FINER THAN 100 MESH MOUNTED ON SAID ROLLER FOR RETRACTION THEREON AND FOR MOVEMENT DOWNWARDLY IN FRONT OF SAID SHELVES AND BETWEEN THE COLD AND WARM AIR CURTAINS. 